I’ve seen people reporting about storage being full, but they were able to remove the files one by one or in a batch with the screen.
You might be better off asking support for help Support Ticket Form
Whats about pressing the three dots in start menu (where you can select your file), edit and check some files and select the bin?
Mine works at least with latest firmware.
We have tried that in the Developer Menu / Experiment / Clear Local Files and it hasn’t worked, hence why we are looking for suggestions and have raised a ticket